Fannie Mae and Freddie Mac securitization volume reached its highest level in nearly four years during the first three months of 2013, according to a new Inside Mortgage Finance market analysis and lender ranking. Ongoing strength in refinance activity was the key. The two government-sponsored enterprises securitized a total of $296.4 billion of refinance loans during the first quarter, accounting for a hefty 83.3 percent of their total business. It was the biggest wave of refi loans to hit the GSE market since the second quarter of 2009, when a whopping $373.7 billion of refinances were securitized by Fannie and Freddie before the Home Affordable Refinance Program reached its stride. While GSE refi business was...[Includes three data charts]